As far as I can see from a quick look;This is based on the LastRrainTipISO value from Cumulus and calculated by the Saratoga template file CU-defs.php which creates the $dayswithnorain variable used in ajax-dashboard.phpSearch for $dayswithnorain in CU-defs.php

The starting point is this entry;$LastRainTipISO = '<#LastRainTipISO>';in the CUtagsT.txt template file in the C:\cumulus\web folder

If you look at this value in either;CUtagsT.txttmp in C:\cumulus\web folderorthe CUtags.php file on the webserver you should see the value Cumulus is delivering.If this is not correct then there is still an error somewhere that needs to be fixed in the cumulus data.